The Kovtun-Son-Starinets (KSS) bound states that the ratio \(\eta /s\)  has a lower bound,
\(\frac{\eta }{s} \ge \frac{1 }{4\, \pi }\) , for all relativistic quantum field theories [1]},[2]} and can be interpreted as the Heisenberg uncertainty principle [3]},[4]} where \(\eta \)  and s are the shear viscosity and entropy density, respectively. However, this conjecture violates for some theories like the Gauss-Bonnet gravity [5]}, Horndeski theory [6]} and massive gravity for \(c_i<0\)  [7]}.
